When a woman has sex for the first time: Does she lose more than one liter of blood?

No, usually a woman does not lose that much blood during her first time having sex.
Sex in this question probably means: sexual intercourse.
That means: The penis is inserted into the vagina.

In some women, the hymen is torn during their “first time”.
Here you can read what that is: https://refu-tips.de/en/i-14-year-old-had-my-period-last-week-i-used-a-tampon-and-i-suddenly-started-bleeding-heavily-i-am-afraid-i-may-have-damaged-my-hymen-what-can-i-do-now/
In some women, the walls of the vagina are injured by the penis.
That means: The penis causes very small tears in the vagina.
In the vagina means: Inside the body.
About half of all women don’t bleed at all during their “first time”.

When a woman bleeds:
Most of the time, it is only a few drops.
This is usually not bad.
The small injuries heal all by themselves.
Sometimes a few more drops appear for a couple of days.
That is not bad either.

If there is more blood:
Then the woman should see a doctor.